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Electrospray deposition
Graziano Magnano
Nanoscience groupSchool of Physics & Astronomy
University of Nottingham
Berlin - 1st October 07
• Instrument: principles and settings
• Results:
• Deposition of PEO on Si(111)
• Deposition of C60 on Au(111)
• Deposition of C60 onto PTCDI / Melamine on Au(111)
• Ongoing and Future work
Graziano Magnano
Berlin - 1st October 07
Overview
Electrospray is widely used in mass spectrometry (MS) as an ionisation source for non-volatile molecules and molecules which break down upon heating.
It’s possible to create gas phase ions directly from a solution of the molecules of interest.
Electrospray ionisation
Especially in MS, electrospray works on large molecules:
• To determine the molecular weight and distribuition of polymers and biomolecules, e.g. DNA.
• To analyse the sequence of proteins or oligonucleotides.
• To analyse drugs, pesticides, carbohydrates or fatty acids with long chains.
Graziano Magnano
Berlin - 1st October 07
Ion production in an electrospray ionisation source has three steps:
Electrospray ionisation: principles
• Aerosol formation;
• Desorbed ion formation;
• Migration to the sample.
• Aerosol formation;
Graziano Magnano
Berlin - 1st October 07
Solvent evaporation Coulombic explosion
Electrospray ionisation: principles
Ion production in an electrospray ionisation source has three steps:
• Aerosol formation;
• Desorbed ion formation;
• Migration to the sample.
Graziano Magnano
Berlin - 1st October 07
Electrospray ionisation: principles
S.J. Gaskell, J.Mass Spectrom. 32 (1997) 667
Ion production in an electrospray ionisation source has three steps:
• Aerosol formation;
• Desorbed ion formation;
• Migration to the sample.
Graziano Magnano
Berlin - 1st October 07
Recently, aside from mass spectrometry, novel applications of electrospray have been used to create:
New Deposition Techniques
Applications
Surface coatings
Functional films
Biological arrays
Electrode coatings
Graziano Magnano
Berlin - 1st October 07
We have developed an electrospray deposition system in which the spray occurs
Instrumentation
In vacuum
At atmospheric pressure
Graziano Magnano
Berlin - 1st October 07
10-2 torr 10-5 torr
Graziano Magnano
Berlin - 1st October 07
In vacuum
Carbon Nanotubes (CNTs)
Electrospray deposition in vacuum: Swarbrick,J.C; Taylor, J.B.; O’Shea, J.N.
Appl. Surf. Sci. (2006) 252, 5622
Polymer (PEO)
Electrospray deposition of carbon nanotubes in vacuum:O’Shea J.N., Schulte K. et al.
Nanotechnology (18) 035707 (2007)
Graziano Magnano
Berlin - 1st October 07
In vacuum
E
P1 P2 P3
S
ca. 70 cm
Solution
Air ~10 Torr-7
Graziano Magnano
Berlin - 1st October 07
At atmospheric pressure
10-7 torr
water-methanol solution
Graziano Magnano
Berlin - 1st October 07
At atmospheric pressure
Graziano Magnano
Berlin - 1st October 07
Deposition of PEO on Si(111)
Graziano Magnano
Berlin - 1st October 07
Deposition of PEO on Si(111)
Graziano Magnano
Berlin - 1st October 07
Deposition of PEO on Si(111)
E
P1 P2 P3
S
ca. 70 cm
Solution
Air ~10 Torr-7
Graziano Magnano
Berlin - 1st October 07
Deposition of C60 on Au(111)
J. A. Theobald, et al., Langmuir, 21, 2005.L. M. A. Perdigão , et al., J. Phys. Chem. B, 110 (25), 2006
Graziano Magnano
Berlin - 1st October 07
Deposition of C60 onto PTCDI / Melamine on Au(111)
Graziano Magnano
Berlin - 1st October 07
Deposition of C60 onto PTCDI / Melamine on Au(111)
2 minutes deposition from a ~ 1mg/ml C60 soln. in Tol:MeCN (3:1)
+1.80V, 0.03nA, 102.3nm x 75.3nm
A – reduced order area
B – Dimers trapped in parallelogram network
C – Heptamers in hexagonal network with 2nd layer growth
Graziano Magnano
Berlin - 1st October 07
Deposition of C60 onto PTCDI / Melamine on Au(111)
A
+1.80V, 0.03nA, 51.0nm x 33.7nm +1.80V, 0.03nA, 23.9nm x 23.9nm
Graziano Magnano
Berlin - 1st October 07
Deposition of C60 onto PTCDI / Melamine on Au(111)
B
+1.80V, 0.03nA, 51.2nm x 40.6nm
Graziano Magnano
Berlin - 1st October 07
Deposition of C60 onto PTCDI / Melamine on Au(111)
+1.80V, 0.03nA, 49.8nm x 30.3nm
C
Graziano Magnano
Berlin - 1st October 07
• Deposition of:
• Nanotubes,
• PbS,
• P3HT, DMP (Soluble Pentacene Precursors),
• C60O, Porphyrin, N@C60.
Ongoing and Future work
• Line of Sight Mass Spectrometry of Electrospray
• Detailed inventory of species in electrospray beam• Attempt to deflect using a biased target could give idea of impact energy
• New housing for spray generation
• Inert atmosphere (Nitrogen)• Precise tip positioning during operation• Heated drying gas
Acknowledgements
• Dr. James O’ Shea• Chris Satterley, Louise Mayor and Anna Rienzo
Funding
• EC Marie-Curie Early Stage Researcher Training NetworkProgram MONET: MOLECULAR NETWORKS AT PHASE BOUNDARIES
…Thank you for your attention
Graziano Magnano
Berlin - 1st October 07